Crowded slums, poor sanitation and unhealthy diets. It’s a potent cocktail and for too many families across the world, a daily reality. Right now, an estimated one billion people live in slums and that number is expected to double by 2030. Slums are where the many deprivations facing the urban poor collide, including lack of access to clean drinking water, sanitation, safe and nutritious foods, sufficient living space, durable housing and secure tenure (UN Habitat). They’re where human waste is routinely emptied into streets, canals, and garbage dumps. And where overcrowding and low rates of immunization and breastfeeding combine to exacerbate the already perilous problems children face.

Children growing up in these surroundings are at a higher risk of death and disease and are more likely to be chronically malnourished (Ezeh et al. 2017). For example, forthcoming World Bank research from Bangladesh shows that children living in slums are 50 percent more likely to be stunted than children living in other urban areas. This doesn’t just have implications for today - children who are stunted early in life go on to learn and earn less, and face a higher risk of chronic disease as they grow older. Tragically, these effects are often passed on to offspring, trapping families in poverty and malnutrition for generations, as per findings in a forthcoming World Bank report called Uncharted Waters.

When a mini-grid project came to Atigagome, a remote island in the middle of Ghana’s Lake Volta, the kerosene lamps people had been using became decorative pieces that were hung on the walls—a reminder that the island’s days of darkness were over. But the village not only gave up kerosene lamps and candles: it also attracted people like Seth Hormuku, who migrated to the island once a stable electricity supply was being provided to the local community.

Eliminating inequality is integral to the Sustainable Development Goals , from ‘universal access’ to water, to ending poverty ‘everywhere’. Yet in a world where the politics of who gets what is increasingly polarised, leaving no-one behind is fundamentally a political project.

In a recent study with WaterAid in Nepal, for example, we found that in rural areas a combination of poverty, caste, and geography have shut the poorest fifth out of politics. While access to water has increased significantly for others, they are lagging behind.

Every city, country or district has its own political rules, most of which aren’t written down. Yet despite all this complexity, experts working on essential services like water, sanitation, health or education can avoid some common political missteps, wherever they work. Here are four most typical ones:

In East Africa and West Africa, about 300 million people living in dryland areas rely on natural, resource-based activities for their livelihood. By 2030, this number could increase to 540 million. At the same time, climate change could result in an expansion of Africa’s drylands by as much as 20%.

They say a picture is worth a thousand words. While visiting the World Bank library the other day, I was struck by how many development publications featured pictures of motor vehicles on their covers, even though most of them covered topics that had little to do with transport. The setting and tone of the pictures varied – sometimes they showed a lone car on a rural highway, sometimes congested vehicles in urban traffic, and sometimes a car displayed proudly as a status symbol – but the prevalence of motorized vehicles as a visual metaphor for development was unmistakable to me: in the public imagination, consciously or otherwise, many people associate development with more use of motorized vehicles.

Indeed, motorization – the process of adopting and using motor vehicles as a core part of economic and daily life – is closely linked with other dimensions of development such as urbanization and industrialization.

Motorization, however, is a double-edged sword.

For many households, being able to afford their own vehicle is often perceived as the key to accessing more jobs, more services, more opportunities—not to mention a status symbol. Likewise, vehicles can unlock possibilities for firms and individual entrepreneurs such as the young man from Uganda pictured on the right, proudly showing off his brand new boda boda (motorcycle taxi).

But motorization also comes with a serious downside, in terms of challenges that many governments have difficulty managing. Motor vehicles can undermine the livability of cities by cluttering up roads and open spaces—the scene of chaos and gridlock in the picture below, from Accra, is a telling example. In addition, vehicles create significant safety hazards for occupants and bystanders alike… in many developing countries, road deaths have effectively reached epidemic proportions. From an environmental standpoint, motorized transport is, of course, a major contributor to urban air pollution and greenhouse gas emissions. Lastly, motorization contributes to countries' hard currency challenges by exacerbating their long-term demand for petroleum products.

Given these challenges, how are developing countries going to align their motorization trajectories with their development goals? What should the World Bank advise our clients about how to manage this process?

Much of West Africa’s population lives along its coastline, where many of its capital cities are located. But though rising seawaters erode it, a study says the “sand river” they create can also protect it.

Developing countries made considerable gains during the 2000s, resulting in a large reduction in extreme poverty and a significant expansion of the middle class. More recently that progress has slowed—and the prognosis is for more of the same, given an environment of lackluster global trade, a lack of jobs coupled with skills mismatches, greater income inequality, unprecedented population aging in richer countries, and youth bulges in the poorer ones. As a result, developing countries are unlikely to close the development gap anytime soon.

In a 2009 paper, David McKenzie and coauthors Chris Woodruff and Suresh de Mel find that giving cash grants to male entrepreneurs in Sri Lanka has a positive and significant return, while giving the same to women did not. David followed this up with work with coauthors in Ghana that compared in-kind and cash grants for women and men. Again, better returns for men (with in-kind working for some

Along the beach in Mondouku, Côte d'Ivoire, a group of fishermen have just returned with their catch. Many of them come from neighboring Ghana, and they tell us that they come to the Ivorian part of the coast because there are more fish here. Still, they explain that the fish are smaller in size and number compared to previous years. The beach they are sitting on is lined with small hotels and cabanas destroyed in a storm surges over the past few years. A bit further down the coast, near the Vridi Canal, we speak with Conde Abdoulaye, who runs the lobster restaurant that his father ran before him. Even at low tide, the water laps against the steps of the restaurant and a retaining wall which he has rebuilt numerous times. He says he knows it is inevitable that at some point the sea will swallow his restaurant, and he will have to leave. He blames the canal for most of the beach erosion, but also acknowledges that changing weather patterns and increasing storms have contributed to the damage.

In Ghana, coastal erosion and rising seas are burying some seaside villages, like Fuveme, which is now completely under sand. As in neighboring countries, hydrocarbon exploration is well underway not too far from the shore, and coastal urban areas are expanding. The fish stock has declined dramatically, and formerly thriving fishing communities are in trouble.